1. Field of the Invention
The present invention relates generally to the bearing retainer art and more particularly to an expandable bearing retainer or locking device construction which is particularly applicable for use on mill roll necks, shafts and the like.
2. Description of the Prior Art
Locking ring assemblies particularly applicable for use on mill roll necks, shafts and the like are available in a wide variety of configurations. These devices are disclosed and claimed in patents which issued to Romolo B. Bianco including U.S. Pat. No. 4,136,989 issued Jan. 30, 1979 entitled “Expandable Annular Cam-Type Locking Device For a Shaft”; U.S. Pat. No. 4,189,251 issued Feb. 19, 1990 entitled “Expandable Annular Locking Device For a Shaft”; and U.S. Pat. No. 4,200,407 issued Apr. 29, 1980 entitled “Bolted Annular Locking Collar For a Shaft”. In addition, the Edward P. Bianco, et al U.S. Pat. No. 5,411,337, issued May 2, 1995 entitled “Axially Guided Locking Ring Assembly” is also directed to a locking device which retains a bearing on a mill roll shaft.
Structures typical of the prior art have a portion or an element disposed in an annular groove of the shaft with an adjusting mechanism disposed between the groove and a bearing to be retained on the shaft. The bearing is typically pressed by the adjusting mechanism against a shoulder of the shaft such as is shown in U.S. Pat. No. 5,411,337.
Mill roll shafts and retainer bearings mounted thereon are complicated by the large size of the associated components and the resultant high axial thrust loads required to maintain the bearings in their desired positions. The construction of the locking ring assemblies for mill roll shafts is further complicated by the dirty, harsh operating environment in which the locking ring assemblies are employed. The intrusion of dirt and contaminants into undesired locations within a locking ring assembly can potentially affect its ability to maintain the required thrust load against the bearing.
There is also a need in the bearing retainer art to maintain pressure on the bearing and to allow for axial movement of the bearing, which is necessary for the bearing to seat properly on the shaft. It is also necessary to have space for thermal expansion of the bearing. Normal requirements of the bearing manufacturers for this bearing movement to occur ranges from 0.010 inch to 0.050 inch, more or less. The prior art devices including U.S. Pat. No. 5,411,337 do not compensate sufficiently for thermal expansion and thus does not provide for axial movement of the chock bearing. Thus, there is a need to provide an axially guided locking ring assembly containing a plurality of adjustable pressure screw assemblies allowing for controlled axial clearance or end play movement of the chock bearing due to thermal expansion.